lt3724 Linear Technology Corporation, lt3724 Datasheet
lt3724
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lt3724 Summary of contents
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... The LT3724 is available in a 16-lead thermally enhanced TSSOP package. , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode is a registered trademark of Linear Technology Corporation. ...
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... and SHDN Pin Currents ................................... 1mA SS Operating Junction Temperature Range (Note 2) LT3724E (Note 3) ..............................–40°C to 125°C LT3724I .............................................–40°C to 125°C Storage Temperature .............................–65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300° ORDER I FOR ATIO LEAD FREE FINISH ...
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... LOAD 10% to 90% or 90 3300pF LOAD LT3724I is guaranteed over the full –40°C to 125°C operating junction temperature range. Note 4: V voltages below the start-up threshold (7.5V) are only IN supported when the V is externally driven above 6.5V. CC Note 5: Operating range is dictated by MOSFET absolute maximum V Note 6: Supply current specification does not include switch drive currents ...
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... LT3724 W U TYPICAL PERFOR A CE CHARACTERISTICS Shutdown Threshold (Rising) vs Temperature 1.38 1.37 1.36 1.35 1.34 1.33 1.32 –50 – 100 125 TEMPERATURE (°C) 3724 G01 CC(LOAD) 8 25°C A 8.1 8.0 7.9 7.8 7.7 7.6 7 (mA) CC (LOAD) 3724 G04 V UVLO Threshold (Rising Temperature 6.5 6.4 6.3 6.2 6.1 6.0 –50 –25 ...
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... G11 V UVLO Threshold (Rising Temperature 4.54 4.52 4.50 4.48 4.46 4.44 4.42 4.40 – 100 125 –25 0 TEMPERATURE (°C) 3724 G14 LT3724 Error Amp Reference vs Temperature 1.234 1.233 1.232 1.231 1.230 1.229 1.228 1.227 50 100 125 –50 – TEMPERATURE (°C) 3724 G12 V UVLO Threshold (Falling) ...
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... LT3724 CTIO S V (Pin 1): The V pin is the main supply pin and should decoupled to SGND with a low ESR capacitor located close to the pin. NC (Pin 2): No Connection. SHDN (Pin 3): The SHDN pin has a precision IC enable threshold of 1.35V (rising) with 120mV of hysteresis used to implement an undervoltage lockout (UVLO) cir- cuit ...
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... MOSFET. In most applications 0.1μF is adequate. The maximum voltage that this pin sees is V ground referred. Exposed Pad (SGND) (Pin 17): The exposed leadframe is internally connected to the SGND pin. Solder the exposed pad to the PCB ground for electrical contact and optimal thermal performance. LT3724 , BOOST + ...
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... LT3724 CTIO AL DIAGRA V IN UVLO (<4V REGULATOR – + SHDN 3 RB BURST_EN – ERROR AMP SOFT-START C C2 DISABLE/BURST R C ENABLE ~ – 1.185V SGND BST UVLO UVLO (<6V) 3.8V INTERNAL ...
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... U OPERATIO (Refer to Functional Diagram) The LT3724 is a PWM controller with a constant fre- quency, current mode control architecture designed for low to medium power, switching regulator applica- tions. Its high operating voltage capability allows it to step down input voltages up to 60V without the need for a transformer ...
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... Start-Up The following section describes the start-up of the supply and operation down to 4V once the step-down supply is up and running. For the protection of the LT3724 and the switching supply, there are internal undervoltage lockout (UVLO) circuits with hysteresis on V shown in the Electrical Characteristics table. Start-up and ...
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... LT3724 can provide full power re- gardless of required duty cycle. Shutdown The LT3724 includes a shutdown mode where all the internal IC functions are disabled and the V reduced to less than 10μA. The shutdown pin can be used for undervoltage lockout with hysteresis, micropower shutdown general purpose on/off control of the converter output ...
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... SENSE current of the supply (See Typical Application on front page). Its value is chosen based on the maximum required output load current. The LT3724 current sense amplifier has a maximum voltage threshold of, typically, 150mV. Therefore, the peak inductor current is 150mV/R The maximum output load current, I inductor current minus half the peak-to-peak ripple cur- rent, Δ ...
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... MOSFET DS(ON) GS data sheet. Use Q an external supply, the MOSFET drive current is not sourced from the internal regulator of the LT3724 and the Q of the MOSFET is not limited by the IC. However, note G that the MOSFET drive current is supplied by the internal ...
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... LT3724 U U APPLICATIO S I FOR ATIO Step-Down Converter: Input Capacitor Selection A local input bypass capacitor is required for buck con- verters because the input current is pulsed with fast rise and fall times. The input capacitor selection criteria are based on the bulk capacitance and RMS current capability. ...
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... The SHDN pin has a precision voltage threshold with hysteresis which can be used as an undervoltage lockout threshold (UVLO) for the power supply. Undervoltage lockout keeps the LT3724 in shutdown until the supply input voltage is above a certain voltage programmed by the user. The hysteresis voltage prevents noise from falsely tripping UVLO ...
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... External Current Limit Foldback Circuit . The value SS1 An additional startup voltage offset can occur during the period before the LT3724 soft-start circuit becomes ac- tive. Before the soft-start circuit throttles back the V in response to the rising output voltage, current as high as the peak programmed current limit (I switched inductor ...
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... Schottky diode conduction loss 1. The V IN currents of the LT3724 and the MOSFET drive currents. The quiescent currents are in the LT3724 Electrical Char- acteristics table. The MOSFET drive current is a result of 3724 F03 charging the gate capacitance of the power MOSFET each cycle with a packet of charge, Q MOSFET data sheet ...
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... These items are illustrated graphically in the layout dia- gram of Figure 9. 1. Keep the signal and power grounds separate. The signal ground consists of the LT3724 SGND pin, the exposed pad on the backside of the LT3724 IC and the (–) terminal The signal ground is the quiet ground and does not OUT contain any high, fast currents. The power ground con- sists of the Schottky diode anode, the (– ...
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... Converters) Minimum on-time ( the least amount of time that TG(ON) the LT3724 is capable of turning the MOSFET on and then off again determined by internal timing delays and the gate charge of the MOSFET. Applications with high input to output differential voltages operate at low duty cycles and may approach this minimum on-time, typically 300nS ...
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... IN 0.1μF 33μF ×2 25V 25V C1 R 1500pF CSS 200k R2 187k R1 R6 10k 40.2k C2 120pF 20 12V to 24V/50W Boost (Step-Up) Converter D1 BAV99 BOOST 4.7M LT3724 3 14 SHDN BURST_EN 1μF V PGND FB 25V SENSE – SGND SENSE ...
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... R SENSE 0.010Ω 10Ω 9 – D1A GSD2004 C5 TDKC453X7R1E226M IN1 OUT2 C = SANYO, OS-CON 16SVP330M OUT1 SEMI, MBRD660 L1 = COILCRAFT VERSAPAC VP5-D83 M1 = VISHAY, Si7852DP LT3724 L1 300μH D1 B170 M1 ZXMN10A07F C VCC 1μF 16V ADJUST I : LED 0.15V I = LED R SENSE R SENSE 0.5Ω 3724 TA03 ...
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... R4 130k R5 14.7k C2 120pF 22 12V Step-Down with V Back Driven CC from V and Ceramic Capacitor in Output Filter OUT 499k V BOOST IN R7 20Ω SHDN LT3724 CSS BURST_EN 1μF V PGND FB 16V SENSE – 15k ...
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... REF 0° – 8° 0.65 (.0256) BSC 4. RECOMMENDED MINIMUM PCB METAL SIZE FOR EXPOSED PAD ATTACHMENT MILLIMETERS (INCHES) *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.150mm (.006") PER SIDE LT3724 4.90 – 5.10* (.193 – .201) 3.58 (.141) 16 1514 6.40 2.94 (.252) ( ...
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... High Voltage Synchronous Regulator Controller Linear Technology Corporation 24 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● Inverting –12V 1.5A Converter 0.1μ 16V BOOST IN 15 0.1μF LT3724 SHDN SW 4 D1A C SS D1B R 12 CSS V CC 200k 1μF 16V ...